Time-Discrete Vibrotactile Feedback Contributes to Improved Gait Symmetry in Patients With Lower-Limb Amputations: A Case Series.

Background. Reduced sensory feedback from lower leg prostheses results in harmful gait patterns and entails a significant cognitive burden because users have to visually monitor their locomotion. Objectives. The purpose of this study was to validate a sensory feedback device designed to help elderly patients with transfemoral amputation to improve their temporal gait symmetry after a training program aimed at associating the vibrotactile patterns with symmetrical walking. Design. This was a prospective quasi-experimental study including 3 elderly patients walking with lower leg prostheses. Methods. During training sessions, participants walked on a treadmill equipped with feedback device that controlled vibrotactile stimulators based on signals from a sensorized insole while provided with visual feedback about temporal gait symmetry. The vibrotactile stimulators delivered short-lasting, low-intensity vibrations synchronously with certain gait phase transitions. During pretraining and posttraining sessions, participants walked without visual feedback about gait symmetry under 4 conditions: with or without vibrotactile feedback while performing or not performing a secondary cognitive task. The primary outcome measure was temporal gait symmetry. Results. with <= 52 hours of training,the participants improved their temporal gait symmetry from 0.82 to 0.84 during the pretraining evaluation session to 0.98 to 1.02 during the follow-up session across all conditions. Following training, participants were able to maintain good temporal gait synmsetry, without any evidence of an increased cognitive burden. Limitations. The small sample size and short follow-up time do not allow straightforward extrapolations to larger populations or extended time periods. Conclusions. Low-cost, gait phase-specific vibrotactile feedback after training combined with visual feedback may improve the temporal gait synmsetry in patients with transfemoral amputation without representing an additional cognitive burden.